For example, in a wheel loader as a working vehicle for civil engineering, hydraulic pressure is necessary in a digging operation, but the discharge amount sometimes may be small. For example, methods disclosed in Patent Citation 1 and Patent Citation 2 serve to detect the performance of a digging operation.
According to Patent Citation 1, it is determined that a digging operation is being performed when at least one of the below-described conditions (1) to (3) is satisfied: (1) the transmission is engaged in a first gear forward gear ratio, (2) the work equipment is in a digging position, and (3) the travel speed of the vehicle is equal to or less than a predetermined amount.
According to Patent Citation 2, when a bottom pressure of the cylinder exceeds a predetermined value, the digging operation is determined to be started and the supply of hydraulic oil is reduced as a method for resolving the problems associated with the method disclosed in Patent Citation 1.
[Patent Citation 1]
    U.S. Pat. No. 6,073,442.[Patent Citation 2]    Japanese Patent Application Laid-open No. 2004-251441.